#!/usr/bin/env perl 
use strict;
use warnings;

my $input = qq#
PEM 0:

PEM 1:

PEM 2:
  State:     Online

PEM 3:
  State:     Online

#;

for my $rec (split /\n\n/, $input) {
    next unless $rec =~ /State:\s+Online/;
    $rec =~ /(PEM \d+)/ or die "Bad input: no PEM in '$rec'!";
    print "$1 is online\n";
}